Sounds like Grafana created a new database somewhere. Which OS are you on and how did you install Grafana?
Package details for the Ubuntu/Debian package - Install Grafana on Debian or Ubuntu | Grafana documentation
which says the grafana.db should be located at /var/lib/grafana/grafana.db so not sure why it is not working for you if you are on Ubuntu/Debian.
Can you check the database name and the paths section in your server settings:
and
